Depends -- If a model has a bunch of body styles and only the most popular is tested, then the manufacturer can skimp on the designs or constructions of the versions that don't get tested.
"""[…] the SuperCrew’s body cage remained “largely intact” with a “low risk of injuries,” the group said. The smaller F-150 SuperCab pickup (pictured at top) scored “marginal” due to “significant intrusion” of the passenger cabin, as the dashboard and steering wheel came “dangerously close” to the dummy’s chest. Since the A-pillars buckled and other body components “seriously compromised the driver’s survival space,” the IIHS rated this F-150’s structure as “poor,” which is below “marginal” and the group’s worst rating."""
Ford did this with the 2015 Ford F-150: http://blog.caranddriver.com/iihs-2015-ford-f-150-crash-test...
"""[…] the SuperCrew’s body cage remained “largely intact” with a “low risk of injuries,” the group said. The smaller F-150 SuperCab pickup (pictured at top) scored “marginal” due to “significant intrusion” of the passenger cabin, as the dashboard and steering wheel came “dangerously close” to the dummy’s chest. Since the A-pillars buckled and other body components “seriously compromised the driver’s survival space,” the IIHS rated this F-150’s structure as “poor,” which is below “marginal” and the group’s worst rating."""